Math 220: Differential Equations

Spring 2026

Department of Mathematics, Grinnell College

Class # Date Reading Brief description Assignment
1 W Jan 21 1.1 - 1.3 Introduction -
First Order ODEs
2 F Jan 23 2.1 Integrating Factor -
3 M Jan 26 2.2 Separable Equations HW 1
4 W Jan 28 2.3 Modeling with First Order ODEs Quiz 1
5 F Jan 30 2.5 Autonomous ODEs and Population Dynamics Lab 0
6 M Feb 2 2.6 Exact ODEs HW 2
7 W Feb 4 2.7 2.6 Euler's Method Exact ODEs Quiz 2
8 F Feb 6 3.1 2.7 Homogeneous ODEs with Constant Coefficients
Euler's Method		 Lab 1
Second Order ODEs
9 M Feb 9 3.2 3.1 Fundamental Solutions and Change of Variables
Homogeneous ODEs with Constant Coefficients		 HW 3
10 W Feb 11 3.3 Characteritic with Complex Roots Quiz 3
11 F Feb 13 3.4 Repeated Roots Lab 2
12 M Feb 16 3.5 Method of Undetermined Coefficients HW 4
13 W Feb 18 3.7 Mechanical and Electrical Vibrations Quiz 4
14 F Feb 20 3.8 Forced Periodic Vibration -
15 M Feb 23 - Q & A HW 5
16 W Feb 25 - Exam 1 Exam
17 F Feb 27 Notes Introduction to Sequences and Series -
18 M Mar 2 Notes Introduction to Sequences and Series HW 6
19 W Mar 4 5.1 Review of Power Series Quiz 5
20 F Mar 6 5.2 Series Solutions Near Ordinary Points -
- Mar 7 - 22 - No Class - Spring Break -
21 M Mar 23 5.3 5.2 Series Solutions Near Ordinary Points -
22 W Mar 25 5.4 Euler's Equation - Regular Singular Points Quiz 6
23 F Mar 27 5.5 Series Solutions Near Regular Singular Points -
The Laplace Transform
24 M Mar 30 6.1 Definition of the Laplace Transform HW 7
25 W Apr 1 6.2 Solution to Initial Value Problems Quiz 7
26 F Apr 3 6.3 Step Functions Lab 3
27 M Apr 6 6.4 Discontinuous Forcing HW 8
28 W Apr 8 - Q&A -
29 F Apr 10 - Exam 2 -
Systems of Linear Equations
30 M Apr 13 7.1 Introduction -
31 W Apr 15 7.5 Constant Coefficients Quiz 8
32 F Apr 17 7.6 Complex Eigenvalues -
33 M Apr 20 7.7 Fundamental Matrices and the Matrix Exponential HW 9
34 W Apr 22 7.8 Repeated Eigenvalues Quiz 9
35 F Apr 24 7.9 Non-Homogeneous Linear Systems Lab 4
Stability
36 M Apr 27 9.1 The Phase Plane Hw 10
37 W Apr 29 9.2 Autonomous Systems and Stability Quiz 10
38 F May 1 9.3 Locally Linear Systems -
39 M May 4 9.4-9.5 Population Dynamics HW 11
40 W May 6 9.7 Periodic Solutions and Limit Cycles Quiz 11
41 F May 8 9.8 Strange Attractors: The Lorenz Equation Lab 5
- See here - Final ExamExam

“The best thing for being sad," replied Merlin, beginning to puff and blow, "is to learn something. That's the only thing that never fails. You may grow old and trembling in your anatomies, you may lie awake at night listening to the disorder of your veins, you may miss your only love, you may see the world about you devastated by evil lunatics, or know your honour trampled in the sewers of baser minds. There is only one thing for it then — to learn. Learn why the world wags and what wags it. That is the only thing which the mind can never exhaust, never alienate, never be tortured by, never fear or distrust, and never dream of regretting. Learning is the only thing for you. Look what a lot of things there are to learn.”

― T.H. White, The Once and Future King